K-trans (MR perfusion)
Citation, DOI & article data
Ktrans is a measure of capillary permeability obtained using dynamic contrast-enhanced (DCE) MR perfusion. It is calculated by measuring the accumulation of gadolinium-based contrast agent in the extravascular-extracellular space.
Increased permeability of vessels in the brain is seen in a variety of conditions:
- glioma: VEGF produced by the tumor reduces the effectiveness of gap junction and creates fenestrations in the endothelium of brain capillaries; this has been shown to correlate with tumor grade 1
- cerebral metastases, which lack blood brain barrier and resemble the vascularity of the parent tissue
- inflammatory lesions (e.g. demyelinating plaques of multiple sclerosis)
It should be noted that how ktrans is interpreted varied according to permeability and blood flow. In situations where permeability is very low (near-intact blood brain barrier) then ktrans is a useful measure of permeability, whereas in situations where permeability is very high (disrupted blood brain barrier) then ktrans will reflect blood flow 3.
- assessment of prostate cancer 2
- 1. Blake MA, Kalra MK. Imaging in Oncology. Springer Science & Business Media. (2008) ISBN:038775587X. Read it at Google Books - Find it at Amazon
- 2. Low RN, Fuller DB, Muradyan N. Dynamic gadolinium-enhanced perfusion MRI of prostate cancer: assessment of response to hypofractionated robotic stereotactic body radiation therapy. AJR Am J Roentgenol. 2011;197 (4): 907-15. doi:10.2214/AJR.10.6356 - Pubmed citation
- 3. Essig M, Shiroishi MS, Nguyen TB et-al. Perfusion MRI: the five most frequently asked technical questions. AJR Am J Roentgenol. 2013;200 (1): 24-34. doi:10.2214/AJR.12.9543 - Free text at pubmed - Pubmed citation